Fastener inserts of varying design for maintaining a fastener within a tapped hole or nut assembly are commonly employed. The use of such fastener inserts offer many advantages including, by way of non-limiting example, providing a more balanced distribution of dynamic and static loads throughout the length of engagement between fasteners and the substrate.
To facilitate the disposition of the fastener insert within a tapped hole or nut, often such inserts are provided with a selectively removable tang. The tang typically includes a notch which is milled, sheared, cut or ground into the insert which allows the tang to be broken off. Once the fastener insert is properly positioned within the tapped hole or nut, pressure is exerted on the tang which causes the tang to break away from the fastener insert body and provide an unencumbered passageway for the insertion of a fastener.
The notch on the removable tang has heretofore been formed via milling, shearing, cutting or grinding using a notch cutter or similar tool prior to coiling the wire. In order to carry out the notching step, the wire must be stopped in the middle of the cycle and prior to the coiling step which adds to the time and expense of manufacturing. While the invention of EP 1060812 A2 attempts to address certain problems associated with stopping or significantly slowing down the production process, this document appears to relate to fastener inserts formed from pre-spooled or pre-rolled wires including milled or sheared notches. As a result of notching and rolling the wire and subsequently coiling the wire, a variation on the insert outside diameter and length can result when utilizing different lots or reels of stainless steel wire. Thus, pre-forming the notch on a whole reel of the material could result in processing problems during the coiling operation. This is based on the fact that if the insert diameter or insert length changes due to variation in the wire spring back, the pre-determined location of the notch will not meet location requirements for proper tang break-off after installation. The helically coiled insert will not be dimensioned correctly. The whole reel of pre-notched wire will have to be scrapped.
Another critical element that can result in material damage or losses is based on the fact that the majority of the wire utilized to manufacture the helically coiled inserts are of small diameter in the areas of 0.010″ to 0.050″. Based on this fact, a pre-notched reel of wire contains thousand and thousands of strands and tens of thousands of notches. It would be very easy for this wire to be tangled, nicked or to break at any of the pre-notched locations if not handled with extreme caution and care. This can further result in additional material losses or operating and set up problems during the coiling operation.
Further, there are certain safety issues introduced into the manufacturing process as a result of milling, such as metal chip formation. Sharpening of the milling apparatus also may pose certain risks.
Yet another problem with heretofore known fastener inserts is the inability to identify similarly shaped inserts from one manufacturer to the next. This is especially problematic where fastener insert quality varies among manufacturers.
In view of the foregoing, a notched fastener insert which solves one or more of the enumerated problems is desirable.